By default, JSSE uses the JSafe code to do RSA operations. This requires converting keys from the JCA RSAPrivateKey format into the JSafe format. The conversion is performed using the (modulues, private exponent) representation for private keys even if the key is available in CRT form.

This means a performance penalty of about factor three for clients when RSA client authentication is used and for servers in all ciphersuites except DHE_DSS and DH_anon.